CVE-2026-70355: Microsoft SharePoint Server Elevation of Privilege Vulnerability

Overview

Severity
High (CVSS 7.3)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Category
Elevation of Privilege
Exploit Status
Not Exploited
Exploitation Likelihood
More Likely
Patch Tuesday
2026-Aug
Released
2026-08-11

Description

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.

FAQ

What privileges could be gained by an attacker who successfully exploited this vulnerability? Successful exploitation could allow an attacker to run script in the security context of the affected SharePoint user and perform actions permitted to that user. There are multiple update packages available for some of the affected software. Do I need to install all the updates listed in the Security Updates table for the software? Yes. Customers should apply all updates offered for the software installed on their systems. If multiple updates apply, they can be installed in any order.

Affected Products (2)

Microsoft Office

  • Microsoft SharePoint Server 2019
  • Microsoft SharePoint Server Subscription Edition

Security Updates (3)

Acknowledgments

<a href="https://th.linkedin.com/in/navaponpremkasem">Navapon Premkasem</a>, <a href="https://www.linkedin.com/in/thimphaching-phengphavanh-458949219/">Thimphaching Phengphavanh</a>, <a href="https://www.linkedin.com/in/songsit-srisura/">Songsit Srisura</a>, <a href="https://www.linkedin.com/in/prawee-lertprasertphan">0x00</a>, <a href="https://www.linkedin.com/in/jattawatt-buranasant-891783107/">Jattawatt Buranasant</a>, <a href="https://www.linkedin.com/in/supawee-foitong/">Supawee Foitong</a>, P1hcn

Revision History

  • 2026-08-11: Information published.